12 Jul
2022
12 Jul
'22
1:47 a.m.
From: Paul Ruizendaal
Note that LSX only holds one process in core and swaps
other processes
(NPROC = 3) out to floppy. It reportedly took several hours for the
Terak to self-compile LSX from source.
If one is working in a simulator, and not a real hardware PDP-11, there's a
'trick' one can use to make life a lot easier - for MINI-UNIX, at least;
I'll
comment on LSX below.
As I report in the MINI-UNIX Computer History Wiki article: "MINI-UNIX uses
the same file system as V6; this allows MINI-UNIX packs to be 'mounted' on V6
systems (either real, or simulated), which is very convenient for working on
them." So just spin up a V6 in the simulator, mount the LSX/MINI-UNIX pack,
and away you go. The V6 toolchain can be used to compile/link kernels; to
link user commands one will need to import the LSX/MINI-UNIX loader (which,
since V6 is source compatible with LSX/MINI-UNIX, is trivial).
LSX is potentially more complex, as it supports _two different_ file system
formats: the standard V6 one, and a 'contiguous' one which is very similar
to the V6 one (rdwri.c has no conditionals on CONTIG; not so alloc.c,
though), but is not fully compatible. So non-contiguous LSX file systems
can be mounted under V6, but not contiguous ones.
Noel